Eight different mountain ranges. That is how they were formed.
2006-10-11 23:30:43
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answer #1
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answered by TMAC 5
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The division of the outer parts of the Earth's interior into lithospheric and asthenospheric components is based on their mechanical differences. The lithosphere is cooler and more rigid, whilst the asthenosphere is hotter and mechanically weaker. This division should not be confused with the chemical subdivision of the Earth into (from innermost to outermost) core, mantle, and crust. The lithosphere contains both crust and some mantle. A given piece of mantle may be part of the lithosphere or the asthenosphere at different times, depending on its temperature, pressure and shear strength. The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which float on the fluid-like (visco-elastic solid) asthenosphere. The relative fluidity of the asthenosphere allows the tectonic plates to undergo motion in different directions.
The plates are around 100 km (60 miles) thick and consist of lithospheric mantle overlain by either of two types of crustal material: oceanic crust (in older texts called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). The two types of crust differ in thickness, with continental crust considerably thicker than oceanic (50 km vs 5 km).
One plate meets another along a plate boundary, and plate boundaries are commonly associated with geological events such as earthquakes and the creation of topographic features like mountains, volcanoes and oceanic trenches. The majority of the world's active volcanoes occur along plate boundaries, with the Pacific Plate's Ring of Fire being most active and famous. These boundaries are discussed in further detail below.
Tectonic plates can include continental crust or oceanic crust, and typically, a single plate carries both. For example, the African Plate includes the continent and parts of the floor of the Atlantic and Indian Oceans. The distinction between continental crust and oceanic crust is based on the density of constituent materials; oceanic crust is denser than continental crust owing to their different proportions of various elements, particularly, silicon. Oceanic crust has less silicon and more heavier elements ("mafic") than continental crust ("felsic").
2006-10-11 22:33:08
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answer #2
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answered by Anonymous
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Sea floor spreading centres
volcanic islands over hot spots and the dating of these.
reversely polarized zones on either side of the spreading centres
circum-pacific volcanic ring of fire
seismic activity along subduction zones
the good fit of continent boundaries like Africa fits into South America.
Geological structures can be traced from one continent to another
The similarity and differences of certain fossil plants and animals between continents depending on when the continents separated.
2006-10-11 23:54:24
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answer #3
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answered by Anonymous
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nicely considering we are speaking technology right here enable me say that no longer something in BIOLOGY makes any experience different than interior the sunshine of evolution so i might threat a wager and say that the biblical clarification is lots off the fact in earth creation besides!
2016-12-16 06:22:42
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answer #4
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answered by ? 3
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Sorry kid, you need to crack open your book and think for yourself. Don't think anyone's going to do your homework for you.
2006-10-11 19:44:06
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answer #5
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answered by John 2
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